The present invention arose in an industry--fast food restaurants--in which there has been considerable recent efforts devoted to designing, making, installing and learning to use exhaust hoods with features such as water-washing of the exhaust gas stream; grease extraction; smoke char and grease aerosol filtration; odor-oxidation and the like all to be neighborly, to abate nuisances, to reduce fire danger and/or to comply with air pollution, safety and/or health laws and regulations of various political jurisdictions.
The best, and in the long run most durable and efficient of these systems, are ones which are well designed, well made, easy to operate correctly and difficult to operate incorrectly, and which receive recommended maintenance.
A successful hood system designed by the present inventor is shown and described in my commonly owned, copending U.S. patent application, Ser. No. 781,418, filed Mar. 25, 1977.
This system and others of the general sort were designed principally for use in connection with the preparation of food for lunches, dinners and similar mid- and late-day meals at which hamburgers and similar fat-containing meat patties and the like are served in a grilled condition. Normally the grease, smoke and odor stream coming off such a cooking operation is intense and the investment in and faithful operation of such a heavy duty hood system is fully justified, even though the energy cost for running such a system is costly and is rapidly becoming even more costly.
Owners, operators and franchisors of fast food restaurants are constantly in search of ways to obtain a higher return on their investment in each store. An amount of attention that a lay person would find almost incredible is devoted to seeming minutiae: e.g. how better to cook a french fry or whether to pierce meat patties before or after they have been at least partially frozen in order that they can be cooked with less energy yet not too many of them broken or disfigured in the piercing step. It is inevitable that part of such attention be devoted to experimenting with also offering foods that would normally be in demand at other times of the day, principally at times that would be breakfast time and snack time for most people. Some people eat hamburgers for breakfast and there is no sense discouraging that, but for most fast food stores there is more business to be gotten at breakfast if grilled sausage patties, fried-egg product or fried-egg substitute, fried ham slices, griddle cakes and similar griddle-fried patties are offered.
The growing practice of fast food restaurants moving into the breakfast and snack serving businesses has "changed the equations" for efficient running of such restaurants and for coping with the need to maintain air quality control for the restaurants' cooking-exhaust gas streams. For such breakfast cooking there is bound to be less beef fat globules, aerosol and char and associated odorous aldehydes and ketones coming off the cooking surfaces, and more steam, lighter oils, fats and the like.
There often is a need, when griddle cooking to conserve heat at the cooking surface by not over-exhausting the air in the vicinity of the griddle.
Because of the overlapping of mealtimes--some are eating their first meal of the day while others are ready for their second or third--and because the foods that are to be cooked are different, it generally makes sense to add to cooking capacity when cooking hours are being expanded into an additional, e.g. breakfast mealtime.
With all of the above in mind it seemed best to take a fresh look at what kind of an exhaust gas stream collector/processor to put over a fast food restaurant's breakfast griddle-cooking work station. As will be seen from the following, it presently seems to the present inventor that the ideal piece of equipment is radically different from the system shown and described in his aforementioned copending U.S. patent application.